Australian Marriage Equality national convener, Alex Greenwich, said, "Our aim is for same-sex couples to be able to marry anywhere in Australia but should a state move first we will support that too."

"If same-sex couples can marry in Victoria it will show the rest of the nation it has nothing to fear from this important and overdue reform."

"We call on Victorian Premier, Ted Baillieu, to allow a Coalition conscience vote in the same way NSW Premier Barry O’Farrell recently allowed a Coalition conscience vote on a Greens’ marriage equality motion."

State legislation allowing same-sex marriages has already been introduced in Tasmania and South Australia.

Constitutional expert, Professor George Williams, has backed the idea of state same-sex marriage laws pointing out that the power to make marriage laws is shared by the states and the Commonwealth.

Mr Greenwich said the push for marriage equality in other countries has often began at the state level.

"In every federation that now has marriage equality, including the US,Canada and Argentina, reform began at a state or provincial level."